JPS6022643B2 - Calcium silicate hydrate aggregate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a novel calcium silicate hydrate-based aggregate in powder or block form suitable for obtaining products with excellent heat insulation properties, low specific gravity, and high strength. A new collection of calcium silicate hydrates that can be molded as a powder without the need for a drying process, and can be molded directly into a lump, with each molded product becoming a lightweight and strong calcium silicate-based product. In particular, calcium silicate hydrate-based aggregates mainly composed of tobermorite-based and/or xonotrite-based calcium silicate hydrates obtained by curing silicic acid raw materials and calcareous raw materials with high-temperature, high-pressure steam. Under observation under an electron microscope, agglomerates exhibiting a flower-like shape that spread radially around a nucleus with a diameter in the range of ~100 Buddhas are irregularly connected and aggregated with intervening voids dispersed. This invention relates to a calcium silicate hydrate-based aggregate characterized by the following properties.

BACKGROUND OF THE INVENTION Calcium silicate products have been widely used as building heat insulating materials, insulators, etc. due to their excellent light weight and heat insulation properties.

Incidentally, in recent years, as a manufacturing method for calcium silicate products, silicate raw materials and calcareous raw materials are dispersed in water to form a slurry, the raw material slurry is cured with high temperature and high pressure steam, and then dehydrated press molding and A method of manufacturing through a drying process has been developed and is now being adopted.

Additionally, a composition for producing a calcium silicate molded body in a slurry state has been devised, in which calcium silicate crystals are formed through high-temperature, high-pressure steam curing.

The above-mentioned compositions thus far have the advantage that they can be easily used in the field and can be used in a variety of applications, since molded bodies can be produced by simply molding and drying.

Furthermore, a composition in which the main component is composed of zonolite needle crystals has been devised, and this composition has sufficient strength comparable to that of a molded product that undergoes crystallization and hardening at the same time by simply molding and drying. It also has the advantage that a molded article having the following properties can be obtained. However, all of the above-mentioned conventional compositions for producing calcium silicate molded bodies are in a slurry state, and a drying step is essential for molding the molded product.
Therefore, it not only inevitably shrinks due to drying, but also has the disadvantage of having to be reshaped into a predetermined shape.

In view of the problems of the composition for producing a calcium silicate molded body based on the above-mentioned prior art, this invention eliminates the drawbacks of the above-mentioned prior art, eliminates the disadvantages, and produces a calcium silicate-based molded body that eliminates the disadvantages. The purpose of the present invention is to provide a calcium silicate hydrate-based aggregate with excellent permeability.

As a result of intensive research to solve the drawbacks of the above-mentioned secondary technology, the inventors found that in agglomerates having a specific form mainly composed of tobermorite-based and/or xonotrite-based calcium silicate, intercalation is not possible. Calcium silicate aggregates, which have voids and aggregate in a low-density state, can be molded into powder without the need for a drying process, and in lumps, they can be formed into compacts as they are, and each compact is lightweight and lightweight. It was discovered that strong calcium silicate could be produced, and this invention was completed.

That is, this invention mainly consists of tobermorite-based and/or xonotrite-based calcium silicate hydrate,
Under electron microscopy, the agglomerates exhibit a flower-like appearance that spreads radially around the nucleus, and the diameter ranges from 5 to 100 Buddhas. In the agglomerates, needle-like crystals are irregularly and firmly connected, and there are voids in the sacs. It is a calcium silicate hydrate-based aggregate characterized by being aggregated with tobermorite and/or
Or it is mainly composed of xonotrite type calcium silicate.

Next, an example of the production method for obtaining the calcium silicate hydrate-based aggregate of the present invention will be described below.

As the raw material, known silicic acid raw materials and calcareous raw materials are used.As the silicic acid raw materials, silica powder, amorphous silica, diatom ferrosilicon dust, etc. can be used. Particularly preferably, average particle diameter A powder of silica stone having a size of about 5 degrees is good, and as a calcareous raw material, slaked lime powder, quicklime powder, etc. can be used.

The above-mentioned siliceous raw material and calcareous raw material are mixed, and the mixture is stored in a well-known autoclave as it is (that is, without adding water and mixing) and reacted under high temperature and high pressure steam to produce a predetermined product. Generate.

Incidentally, the reaction conditions can be appropriately selected depending on the type of raw material used, particle size, etc. For example, silica powder (purity 98
% or more, if average particle flea 51) and slaked lime powder (special slaked lime) are used, the Ca○/Si02 molar ratio of the raw material is 1
．． When the reaction is carried out in saturated steam at 200 DEG C. and a pressure of 15 k9 for 6 to 1 time, a xonotrite-based calcium silicate hydrate is mainly produced.

Note that this product may also contain some tobermorite-based calcium silicate hydrate.

In addition, the Ca○/Si02 molar ratio of the raw material was set to 0.8, and 20
If the reaction is carried out for 3 to 1 feeding time at 0°C and a pressure of 15k9/kg, tobermorite-based calcium silicate hydrate is mainly produced. Note that this product may partially contain zonolite calcium silicate hydrate.

The reaction product obtained in this way is an aggregate composed of calcium silicate hydrate as a living body, and when heated in a high-temperature, high-pressure steam reaction, it is obtained as a powder, which is then placed in a mold and allowed to stand still for reaction. As a result, a lump-like molded product was obtained, and the aggregate was composed of a large number of aggregates bonded together and aggregated with intervening voids, and the aggregate was observed with a 350-degree electron microscope. Time,
It is visually recognized that the flower has a flower-like appearance with the nucleus as the center and spreading radially. This state is as shown in the scanning electron micrographs of FIGS. 1 and 2. As mentioned above, the aggregate of the present invention is obtained by curing a raw material powder mixture with high temperature and high pressure steam, and during the reaction, tobermorite-based and/or xonotrite-based calcium silicate hydrate is added. An aggregate of mainly agglomerates is formed, and the shape of the agglomerates is unique in that it is flower-like and spreads out radially.

Further, the size of the agglomerates is usually in the range of 5 to 100 mm. When molding a predetermined molded article, such as a heat insulating material for construction, using the powdered calcium silicate hydrate-based aggregate of the present invention, for example, press molding is sufficient and no drying step is required. Alternatively, in the case where solidification is carried out simultaneously with the reaction, a molded body mainly composed of bulk calcium silicate hydrate can be obtained as is, and a drying step is not required. Since the agglomerates of calcium silicate hydrate come into contact with each other and become entangled, the molded product exhibits good heat insulation properties and is lightweight and strong.

Next, embodiments of the invention will be described. <Example 1> Silica stone powder (average particle size 5 French) and slaked lime powder were
○: Si02 molar ratio of 0.83:1.00 was not added, but the powder was mixed uniformly, filled into a mold, and then placed in a well-known autoclave under saturated steam pressure at 200°C and pressure 1.
When the mixture was reacted for 8 hours at 5 kg/kg, a block-like molded product was obtained.

When this compact was analyzed by powder X-ray crystal diffraction,
It was a calcium silicate hydrate mainly composed of 11A tobermorite.

Furthermore, a scanning electron micrograph of the fractured surface of the molded body at 350 M is shown in FIG.

<Example 2> The same raw materials as in Example 1 above were used at a Ca○:Si02 molar ratio of 1
．． Mixed at a ratio of 00:1.00, filled into a mold, placed in an autoclave, heated to 20,000 yen, and saturated steam pressure 15 k9/
After reacting for one hour, a lump-like molded body was obtained.

When this compact was analyzed by powder X-ray crystal diffraction, it was found to be a calcium silicate hydrate based on xonotrite. FIG. 2 shows a scanning electron micrograph of the fractured surface of this molded body at a magnification of 350 mm.

<Example 3> The same raw materials as in Example 1 were used at a Ca0:Si02 molar ratio of 0. After mixing at a ratio of 1.00%, put it in an autoclave and heat it in saturated steam at 200oo, pressure 1.
After reacting for 4 hours at 5k9/m, a powdery aggregate was obtained.

When this aggregate was analyzed by powder X-ray crystal diffraction,
It was a calcium silicate hydrate with tobermorite as its king.

By pressing this powdery aggregate, a molded body for use as a building insulation material was obtained.

<Example 4> After mixing the same raw materials as in Example 1 at a Ca○:Si02 molar ratio of 1.00:1.00, the mixture was placed in an autoclave and heated in saturated steam at 20,000°C under pressure. 1
After reacting for 8 hours at 5 kg/me, a powdery aggregate was obtained.

When this was analyzed by X-ray crystal diffraction, it was found to be a calcium silicate hydrate mainly composed of xonotrite.

Furthermore, by pressing this powder, a molded body for use as a building insulation material was obtained.

Various molded products were molded using the test pieces obtained in Examples 1, 2, 3, and 4, and the results of physical tests on the molded products are shown in the following table.

*The zonotrite molded body was heat-treated at 1000°C for 3 hours, and the tobermorite molded body was heat-treated at 650°C for 3 hours.

It can be seen that all of the above samples had essentially negligible drying shrinkage rates, did not require a drying process, and were lightweight and strong molded products. As mentioned above, the calcium silicate hydrate-based aggregate of the present invention has the advantage of being lightweight and strong when molded into building insulation materials, etc., basically without requiring a drying process. effect is produced. Furthermore, when the aggregate of this invention is in the form of a powder, compared to the case where it is in the form of a slurry,
It has the advantage of not only being able to be stored for a long time, but also being easy to transport. Furthermore, in the case of powder, a predetermined molded product with sufficient strength can be produced by simply adding an appropriate amount of water and molding and drying.

In addition, xonotrite-based and/or tobermorite-based calcium silicate hydrates combine irregularly to form a large number of agglomerates through dispersed voids, and the diameter of the agglomerates is 5 to 10.
Because it has a flower-like shape that spreads out in a radial pattern, it has a low specific gravity, high strength, and good compressibility, so it is useful for manufacturing molded products such as building insulation materials and as fillers for reinforcing various materials. It has an effect suitable for

[Brief explanation of the drawing]

Figures 1 and 2 show an aggregate of calcium silicate hydrate according to the present invention. Figure 2 is an explanatory diagram of 350 sounds of an aggregate mainly composed of xonotrite calcium silicate hydrate. Figure 1 Figure 2

Claims (1)

[Claims] 1 Under observation with an electron microscope, the agglomerates exhibiting a flower-like appearance with a radial spread around the nucleus and a diameter in the range of 5 to 100 μ are irregularly connected and have intervening voids dispersed. Tobermorite-based and/or characterized by
Calcium silicate hydrate aggregate mainly composed of xonotrite calcium silicate hydrate.